Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
van hanh » van thanh, ban hanh, van anh
sach ky » sac ky, sach y, sach ty
hanh ve » hanh vi, hanh va, hanh kem
cac bac » cac bai, cac ban, cac cach
cac tac » cac toc, cac dac, cac tai
hieu ve » hieu va, hieu van
cu tren » tu tren, dua tren
co hoi » co hoc
ve cu » ve cau, ve chu, ve cua

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach ky nang ((co hoi) OR (co loi)). hieu ve ((cac tac) OR (cac bac)) van hanh ve cu tren~.
• Adding a wildcard symbol may retrieve word variants: thuat sach ky nang ((co hoi) or (co loi)). hieu ve ((cac tac) or (cac bac)) van hanh ve cu tren*.